Designing Better Organic Solar Cells

While the theories behind solar cells are certainly promising, current technology is struggling to deliver the performance and affordable cells we want. Silicon solar cells have decent performance but can be exceedingly expensive while organic cells are cheaper but are poorer performers. Researchers at Northwestern University however have recently found a way to potentially increase an organic solar cell's effectiveness, thanks to a genetic algorithm.

Genetic algorithms mimic evolution by combining successful designs and analyzing the offspring for success, before repeating the combining process. The researchers put such an algorithm to work finding a new pattern for a scattering layer, placed on top of an organic solar cell. The scattering layer scatters what light falls on the solar cell in order to increase the time the light is within the cell, thus increasing the amount of light that can be converted to electricity.

After twenty generations of the genetic algorithm, the researchers had their new scattering layer design that performs three times better than a thermodynamic limit for how long a photon can exist within a semiconductor. Now the researchers are working with others at Argonne National Laboratory to create and test the scattering layer design on an organic solar cell.